Mechanical line latch



April 7, 1970 W. A. WINTERS MECHANICAL LINE LATCH Filed July 24, 1968 FIG. 3

INVENTOR WILLIAM A. WINTERS FIG.

@ f '0 ma ATTOR N EY United States Patent O 3,504,743 MECHANICAL LINE LATCH William A. Winters, Calgary, Alberta, Canada, assignor to Dresser Industries, Inc., Dallas, Tex., a corporation of Delaware Filed July 24, 1968, Ser. No. 747,318 Int. Cl. E21b 23/00 US. Cl. 166-214 6 Claims ABSTRACT OF THE DISCLOSURE A latching mechanism for use with wire line operated well tools that includes a latch member engageable with the lower end of a conduit extending into a well bore to prevent upward movement of the wire line, latching mechanism, and well tool upwardly through the conduit. A release arm is incorporated in the latching mechanism to release the latching mechanism when the release arm is lowered below the lower end of the conduit whereby the wire line, latching mechanism and well tool can be raised through the conduit.

BACKGROUND OF THE INVENTION This invention relates generally to an improved releasable latching device. More particularly, but not by way of limitation, this invention relates to an improved latching apparatus for releasably connecting wire line operated well tools in the well bore to prevent upward movement of such well tools through the well bore when latched and to permit the upward movement of such tools therethrough when unlatched.

As is well known to those familiar with the perforating of oil and gas wells or the like, the detonation of the perforating charges tends to drive the perforating gun upwardly in the well bore. If sufficient liquid is present in the well bore, the gun moves upwardly for only a short distance. However, when little or no liquid is present, the gun may move upwardly a sufficient distance to damage or break the supporting wire line. It is believed that such damage results from a kink or knot being formed in the wire line as the gun moves up and then down. Therefore, it is highly desirable to provide some means for preventing such upward movement of the gun in all wells and, most particularly, to prevent such upward move ment in wells containing little or no liquid, such as in gas wells.

Prior to this invention, latching mechanisms for use with wire line actuated tools were of relatively complex nature and generally were of two types. Latching mechanisms of first type are more commonly known as anchors. Such anchors generally utilize one or more sets of radially expandable slips having teeth on the exterior thereof arranged, when the slips are expanded, to holdingly engage the interior of the conduit through which the tool is run. The anchors are relatively complex in that they necessarily contain a large number of working parts including some means for expanding the slips by relative movement whereby the slips will be moved into holding engagement and some means for the slips releasing when desired. The various parts are generally constructed by relatively expensive machining to hold the close tolerances required for proper operation.

The second type of latching mechanisms involve the use of a landing nipple, that is, a section of pipe having an interior flange therein that is engaged by radially expandable collet fingers or similar devices carried by the latching mechanism. Again, such devices are of necessity relatively complex and expensive since they include many relatively moving parts to expand and contract the 3,504,743 Patented Apr. 7, 1970 collet fingers whereby the device will be latched in the conduit and released therefrom as desired.

SUMMARY OF THE INVENTION This invention provides an improved latching apparatus for use in a well bore having a conduit disposed therein. The apparatus includes a hook member having a hook-shaped end portion arranged to releasably engage the conduit; a supporting member movable through the conduit and pivotally supporting the hook member, and a release member also supported by the supporting member and engageable with the hook member to release the hook-shaped end portion from the conduit when it is desired to retrieve the apparatus from the well bore.

An object of this invention is to provide an improved latching mechanism that positively prevents upward movement of the tool through the conduit.

One other object is to provide an improved latching mechanism that may be quickly and easily released to permit withdrawal of the tool through the conduit.

Another object of this invention is to provide an improved latching mechanism that is very simple in construction and, yet, is extremely effective in performing its intended functions.

A further object of the invention is to provide an improved latching mechanism that is economical to manufacture and requires little or no maintenance during its service life.

The foregoing and additional objects and advantages of the invention will become more apparent as the following description is read in conjunction wtih the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a cross-sectional view of a portion of a well bore showing the lower end of a conduit disposed therein with a latching mechanism, constructed in accordance with the invention, shown in elevation.

FIGURE 2 is an enlarged cross-sectional view of a portion of FIGURE 1 showing a portion of the conduit and showing, in more detail, the latching mechanism constructed in accordance with the invention.

FIGURE 3 is a cross-sectional view similar to FIG- URE 2, but illustrating the latching mechanism in another position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing and to FIG-URE 1 in particular, shown therein and generally designated by the reference character 10, is a well bore having a casing 12 extending therethrough. The annular space between the well bore wall and the casing 12 is filled with a cementitious material 14.

Extending into the interior of the casing 12 is a. conduit or tubing 16 having a lower end 18. As shown schematically in FIGURE 1, a packer 20 is positioned between the exterior of the conduit 16 and the interior of the casing 12. In the usual well completion situation, the packer 20 is utilized to isolate a production formation below the conduit 16, to maintain the conduit 16 centralized in the casing 12, and to anchor the conduit 16 in the well bore 10.

A wire line or cable 22 extends downwardly into the interior of the conduit 16 from the surface of the well. Although not shown, the upper end of the wire line 22 is connected with the usual surface mounted apparatus for paying out and reeling in the wire line 22 as it is moved through the conduit 16. When the wire line 22 is utilized to actuate well tools suspended thereby that require an electrical signal, the wire line 22 will, of course, include one or more conductor members (not shown) as is Well known in the art.

A cable head 24 connects the wire line 22 with the upper end of a latching assembly 26. The lower end of the latching assembly 26 is connected with a well tool (illustrated in FIG. 1 as a perforating gun assembly 28) to perform the desired operations in the well bore 10.

It will be understood that the perforating gun assembly 28 will be suitably connected with the conductor members (not shown) carried by the wire line 22.

Furthermore, it will be understood that the arrangement of apparatus illustrated in FIGURE 1 is presented by way of example only and that various spacers, selectors, control heads and other devices commonly used in oil and gas wells and the like could be included as desired or required.

As shown in FIGURE 2, the latching assembly 26 includes a body or supporting member 30 having a hollow interior 32. A slot or opening 34 extends through the side wall of the body 30 into the interior 32. A shaft 36 extends transversely through the body 30 substantially perpendicularly to the opening 34.

A hook 38 has an upper end portion 40 pivotally supported by the shaft 36. The hook member 38 also has a lower, hook-shaped end portion 42 that is arranged to engage the lower end 18 of the conduit 16 as will appear more fully hereinafter.

A hook release arm 44 is also pivotally supported on the shaft 36. The hook release arm 44 includes a projecting lug 46 that is engageable with the hook 38 as also will appear more fully hereinafter.

As also shown in FIGURE 2, both the hook 38 and the release arm 44 extend outwardly of the hollow interior 32 of the body 30 through the opening 34 therein into engagement with the interior of the conduit 16. The hook 38 and release arm 44 are illustrated in the positions they occupy as the latching assembly 26 is moved downwardly through the conduit 16. The hook 38 and release arm 44 are maintained in this position by a spring 48.

The spring 48 encircles the shaft 36 and has one end 50 engaging the release arm 44. The opposite end 52 of the spring 48 engages the hook 38. The arrangement of the spring 48 is such that it pivots the release arm 44 about the shaft 36 in a clockwise direction, as seen in FIGURE 2, and that it pivots the hook 38 in a counterclockwise direction about the shaft 36 as also seen in FIGURE 2.

OPERATION After the tubing or conduit 16 has been placed in the Well bore 10, the wire line, cable head 24, latching assembly 26 and perforating gun assembly 28 (or other suitable well tool) are assembled in the desired manner and extended into the tubing 16. As the apparatus passes downwardly through the tubing 16, the various components of the latching assembly 26 assume the position illustrated in FIGURE 2.

As shown therein, the hook 38 and release arm 44 are biased outwardly into sliding engagement with the interior of the tubing 16 by the spring 48. The rounded surfaces on the release arm 44 and on the hook-shaped end portion 42 of the hook 38 permit the apparatus to pass freely through the conduit '16.

When the hook-shaped end portion 42 passes below the lower end 18 of the conduit 16, the bias of the spring 48 pivots the book 38 relatively outwardly so that the hook-shaped end portion 42 is in a position to engage the lower end 18 of the tubing 16. At this time, downward movement of the apparatus through the tubing 16 is stopped and upward strain or tension is taken on the wire line 22, lifting the apparatus upwardly through the tubing 16 until the hook-shaped end portion 42 engages the lower end 18 of the tubing 16 as shown in FIG- URE 1. In this position, further upward movement of the .4 apparatus through the tubing 16 is positively prevented.

With the apparatus securely latched in the tubing 16 as shown in FIGURE 1, the charges (not shown) in the perforating gun assembly 28 are detonated to form the desired perforations in the wall of the well bore 10. It will be appreciated that since the apparatus is positively latched against upward movement, the detonation of the explosive charges cannot force the perforating gun assembly 28 upwardly in the tubing 16. As previously mentioned, with little or no fluid in the well bore 10, detonation of the explosive charges may drive the gun assembly 28 upwardly in the tubing 16. If the wire line 22 breaks, the gun assembly 28 will drop into the Well bore and require an expensive and time consuming fishing job. However, with the latching apparatus 26 securely engaging the lower end 18 of the tubing 16, upward movement of the gun assembly 28 in the well bore is positively prevented avoiding any possibility of dropping the gun assembly 28 into the well bore.

To release the latch assembly 26, the wire line 22 is lowered, lowering the latching assembly 26 until the release arm 44 is disposed below the lower end 18 of the tubing 16. When the release arm 44 passes below the lower end 18 of the tubing 16, the spring 48 biases the release arm 44 in a clockwise direction pivoting it outwardly.

The wire line 22 is then raised upwardly through the tubing 16 so that the release arm 44 engages the lower end 18 of the tubing. When the release arm 44 engages the lower end 18, the release arm 44 is pivoted further in the clockwise direction until the lug portion 46 thereon engages the book 38, forcing the hook 38 through the opening 34 into the interior 32 of the body 30 and out of engagement with the tubing 16.

As the latch assembly 26 is moved upwardly in the Well bore, the book 38 and release arm 44 are in the position illustrated in FIGURE 3. As shown therein, the lug portion 46 on the release arm 44 is in engagement with the hook 38 retaining the hook 38 in the retracted position. The outer end of the release arm 44 engages the interior of the conduit 16 as the wire line 22, latching assembly 26 and gun assembly 28 are moved upwardly in the well bore positively retaining the hook 38 in a position wherein it cannot engage the tubing 16. Thus, the latching assembly 26 is retained positively in the disengaged position, as illustrated in FIGURE 3, until the apparatus reaches the surface of the well bore 10.

As can be appreciated from the foregoing detailed description of the structure and operation of the latching assembly 26, this invention provides an improved latching mechanism that is simple in construction and, yet, one that will positively latch the apparatus in the well bore until such time as desired to retrieve the apparatus therefrom. Also, the invention provides a latching apparatus that is positively disengaged from the tubing 16 whereby the hook 38 cannot inadvertently engage the tubing 16 as the apparatus is withdrawn from the well bore.

Having described but a single embodiment of the invention, it will be appreciated that such embodiment is presented by way of example only and that many changes and modifications can be made thereto without departing from the spirit of the invention or from the scope of the annexed claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for use in a well bore wherein a conduit having a lower end is disposed therein, said apparatus comprising:

hook means having a hook-shaped end portion arranged to releasably engage the lower end of the conduit;

supporting means movable through the conduit for pivotally supporting said hook means; and

release means operably supported by said supporting means for engaging said hook means to release said hook-shaped end portion from said conduit.

2. The apparatus of claim 1 and also including resilient means engaging said hook means for pivoting said hook means on said supporting means to move said hookshaped end portion relatively away from said supporting means and toward the conduit.

3. The apparatus of claim 1 wherein said supporting means includes a hollow elongated member having an opening in the side thereof size to receive said hook means and release means.

4. The apparatus of claim 3 wherein said supporting means also includes a shaft member extending into the hollow interior thereof to pivotally support said hook means and release means.

5. The apparatus of claim 4 and also including resilient means engaging said hook means and release means to pivot said hook means and release means about said shaft member and relatively outwardly of said supporting means through said opening.

6. Apparatus for use in a well bore wherein a conduit having a lower end is disposed therein, said apparatus comprising:

a hollow body member moveable through the conduit,

the wall thereof;

a shaft member extending through said body member generally perpendicularly to said opening;

a hook member having a first end portion pivotally mounted on said shaft member and having a second hook-shaped end portion for releasably engaging the lower end of the conduit;

a release member having a first end portion pivotally mounted on said shaft member and a second end portion engageable with the conduit, said release member being engageable with said hook member to pivot said hook-shaped end portion through said opening into the interior of said body member and out of engagement with the conduit; and

spring means engaging said hook member and release member to pivot said members in opposite directions about said shaft member.

References Cited UNITED STATES PATENTS 1,690,536 11/1928 Hartman 166132 2,229,581 1/194'1 McLaughlin 166214 2,960,165 11/1960 Schramm 166-132 X 2,999,542 9/1961 Myers 166-214 X 3,045,748 7/1962 Schramm 166214 X 3,391,744 7/1968 Burch 166243 X said bod member having an elongated opening in DAVID BROWN Pnmary Exammer US. Cl. X.R. 

